I found this wheel last year, a friend of my printed it. Looks very good.
I should suggest not to remove the head of the wheel, just remove the wheel completely, the pull with some force the Pin out, by turning it around an pulling together. Then you can use the same PIN to put the wheel back on the explorer without much trouble. Think to put first some epoxy glue in the hole before putting the wheel back so you are sure that it will be fixed good for the next 30 years ;-)
I bought an old broken explorer for a few euro and took it completely apart to see how everything was put together. I can tell you, you can only change the wheels, not the steering wheel, that is not removable or replaceable. Everything in the explorer is glued together and pins are not able to be removed.
